Grinding wheel truing apparatus



1941- c. G. FLYGARE 2,258,568-

GRINDING WHEEL 'I 'RUING APPARATUS Filed Jan. 22, 1940 2 Sheets-Sheet 1CHFL EFL YEHHE Oct 7, 1941. c. G. FLYGARE GRINDING WHEEL TRUINGAPPARATUS 2 Sheets-Sheet 2 Filed Jan. 22, 1940 CHRL EFLYEHEE II: hr"

Patented Oct. 7, 1941 Carl G. Flygare, Worcester, Mass., assignor toNorton Company, Worcester, Mass., at corporation of Massachusetts IApplication. January 22, 1940, Serial No. 314,968

3 Claims.

The invention relates to grinding machines, and more particularly to agrinding wheel truing apparatus for truing an irregular form or I shapeon a grinding wheel.

. One object of the invention is -to provide a formed wheel truingapparatus for truing an irregular form or shap upon the operative faceof a grinding wheel. Another object of the invention is to provide afootstock truing device for producing an irregular shape or form on theperiphery of a grinding wheel. A further object of the invention is toprovide aform truing apparatus for a grinding machine in which afollower is moved through an irregular path to produce a transversmovement of the truing tool to reproduce a desired and predeterminedshape on the periphery of the grinding wheel. Other objects will be inpart obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexemplified ample, that shown in the prior U. S. patent to Wallace H.Wood, No. 2,071,677, dated February 23, 1937. The wheel I8 is arrangedto be fed transverselyby means of a-grinding wheel feeding mechanism(not shown) such as, for example, that shown in the prior U. S. PatentNo. 2,071,677, above referred to, to which reference may be had fordetails of disclosure not contained herein. This feeding mechanism maybe manually actuated or it may be automatically and intermittentlyactuated either continuously or in timed relation with the longitudinalreciprocatory movement of the table II.

The table II may be traversed manually by means of a manually operabletable traversing tatable shaft 22 which is in turn journalled in in thestructure to be hereinafter described, and

the scope of the application of which will be indicated in the followingclaims.

In the accompanying drawings in which is shown one of various'possibleembodiments of the mechanical features of this invention,

Fig. 1' is a plan view of a portion of a grinding machine, showing thegrinding wheel form truing apparatus in operative position;

Fig. 2 is-a fragmentary end elevation of a grinding machine having theimproved form wheel truing apparatus shown in an operative position. I

Fig. 3 is a combined fragmentary front elevation, taken approximately onthe line 3-3 of Fig. 1, and an electrical diagram of an electricalsafety interlock.

A grinding machine has been illustrated in the drawings having a base l0which supports a longitudinally movable work supporting table II on theusual V-way l2 and flat way I3. The table It supports a swivel table M,the upper surface of whichis formed as a dovetailed shaped surface whichmates with a correspondingly shaped surranged for a transverse feedingmovement, such as is common practice in the old and well knowncylindrical grinding machines such as, for exsuitable bearings withinthe'base Ill. The shaft 22 carries a gear 23 on its outer end whichmeshes with a gear 24 supported on a rotatable shaft 25. A manuallyoperable traverse ,wheel 26 is 'also mounted on the shaft 25 and isfixedly mounted to rotate with the gear 24. apparent from the foregoingdisclosure that when the hand traverse wheel 26 is rotated in eitherdirection, a longitudinal traversing movement will be imparted to thetable II through the gear and rack mechanism above described.

If desired, the table it maybe reciprocated by a power operatedmechanism such as, for example, afluid pressure cylinder 30 whichissupported on the under side of the table I I (Fig. 2). A fluid pressurepump 3| (Fig. 3) is driven by means of an electric motor 32 to conveyfluid under pressure to the cylinder 30 so as to reciprocate the tabl IIas desired. The hydraulically operated table reciprocating mechanism hasnot been illustrated indetail, since this mechanism is identical withthat shown in the above-mentioned U. S. patent to Wood, No. 2,071,677,to

which reference may be had for details of disclosure-not containedherein.

The'improved form wheel truing mechanism is preferably supported on thefootstock I6 and comprises .a transversely movable slide member 35 whichis arranged to slide transversely within an aperture formed integralwith the footstock IS. The right-hand end of the slide 35 (Fig. 2) isprovided with 'a-downwardlyextending arm 36 which is rigidly fastened tothe end of the slide 35. The arm 36 supports a diamond or truing tool.31 which is arranged to engage the pcriphery of the grinding wheel I8at a point sub- It will be readily stantially in a horizontal planepassing through the wheel and work axis. An inverted U-shaped bracket 38is fixedly mounted on the left-hand end of the slide 35 (Fig. 2). Thebracket 38 supports a V-shaped follower member 39 which is arranged toengage the peripheral surface of a forming bar 48. The forming bar 48 isof a circular cross section so that when one surface becomes worn, theforming bar 48 may be rotated a slight amount to present a fresh,correctly shaped forming surface. The U-shaped bracket 38 straddles theforming bar 48 so'that the follower bears the same relation to theforming bar 48 as the diamond truing tool 31 does to the grinding wheelI8. The follower 39 is preferably accurately shaped to correspond withthe shape of the truing tool 31 so that when the follower .is traversedrelative to the forming bar 48, it

the slide 35 in a forward direction, that is, to-

Ward the grindingv wheel IS. The spring 4| is contained within anaperture 42 formed within the slide 35. One end of the spring 4| issupported by means of a stud 43 carried by the slid 35. The other end ofthe spring 4| is supported by a stud 44 which is carried by a block 45fastened to the footstock frame by means of screws 48. The spring 4|, asabove explained, serves normally to maintain the follower 39 inoperative engagement with the surface of the forming bar 48 during atruing operation.

The forming bar 48 is supported by a slide 41 which is formed withintegral projecting arm-s 48 and 49 (Fig. l). The arms 48 and 49 areprovided with apertures, which are arranged to receive cylindricalportions 58 and formed on opposite ends of the forming bar 40. Bindingor clamping screws 52 and 53 are provided in the arms 48 and 49 by meansof which the forming bar 48 may be rigidly secured in an operativeposition. When a surface of the forming bar 48 becomes worn, a newforming surfac may be presented by loosening the screws 52 and 53 andthen rotating the bar 48 to present a fresh forming surface.

The slide 41 is supported by a bracket 55 which is formed with avertically extending portion 58 having a dovetailed surface 51 formedtherein. The dovetailed surface 51 mates with a dovetailed slide surfaceformed on the slide 41. The bracket 55 is alsoprovided with ahorizontally extending base portion 58 which is'supported on a planesurface 59 formed on the upper portion of the footstock l8.

In order to facilitate adjustment of the position of th forming bar 48so as to align its axis relative to the path of travel of the table II,the bracket 55 is preferably adjustably supported on the footstock H bymeans of a pivot stud 88. A pair of adjusting screws 8| and 82 aresupported in bosses 83 and 84, respectively, which are formed integralwith the footstock l8. The screws 8| and 82 bear against the uppersurface of the base portion 58 of the bracket 55 (Fig. 1). Bymanipulating the screws 8| and 82, respectively, the bracket 55 may beswivelled about the stud 88 to position the forming bar 48 as desired.Lock nuts 85 and 88 are provided to lock the screws 8| and 82 inadjusted position. Clamping screws 81 and 88 are provided rigidly toclamp the base portion 58 of the bracket 55 rigidly in adjusted positionon the footstock |8.

The'

clamping screws 81 and 88 pass through elongated slots 89 and 18,respectively, formed in the base portion 58 and are screw threaded intothe footstock 8. After the bracket 55 has been adjusted to align theforming bar 48, the clamping screws 81 and 88 may then be actuatedrigidly to clamp the bracket 55 and the forming bar 48 in the desiredadjusted position.

A bracket 15 is fixedly mounted on the slide' 41 by means of screws 18and 11 (Fig. 1). The bracket 15 projects through an elongated clearanceslot 18 formed in the vertical portion 58 of the bracket 55. The bracket15 supports a rod 19 which is held in a fixed position with respect tothe bracket 15 by means of a nut 88 screw threaded onto the end of therod 19. The slide 35 supporting the diamond or truing tool 31 istraversed longitudinally with the footstock l8 and the table to pass thetruing tool 31 across the peripheral surface of the grinding wheel |8 totrue the same. sired transverse movement to the slide 35, the slide 41supporting the forming bar 48 is held stationary during the truingoperation as the bracket 55 moves longitudinally with the table II andfootstock I8.

In order to hold the slide 41 stationary, a bracket 8| (Fig. 2) isfixedlysupported on the front of the machine base l8. The bracket 8|serves as a support for a pivot stud 82' which in turn supports apivotally mounted arm 83. The

arm 83-is provided with an open slot 84 at its upper end which isarranged to engage a reduced end portion 85 on the rod 19. When it isdesired to true the grinding wheel, the table is moved toward the leftuntil the arm 83 may be swung into an operative position with the slot84 in engagement with the reduced end portion 85 on the rod 19. A nut 88which is screw threaded onto the reduced end portion 85 serves to clampthe arm 83 fixedly to the rod 19. When the arm 83 is clamped in anoperative position (Figs. 1 and 2), the table II may be traversedlongitudinally to traverse the diamond 31 across the periphery of thegrinding wheel l8. The rod 19 serves to hold the slide 41 stationarywhich in turn holds the forming bar 48 stationary while the table II,the footstock l8 and the transverse slide 35 and truing tool 31 togetherwith the bracket 55 are traversed longitudinally either by rotation ofthe hand wheeel 28 or by means of the hydraulic table traverse mechanismabove referred to. The travel of the follower 39 along the surface ofthe stationary forming bar 48 serves to transmit a transverse movementto the slide 35 and to the diamond or truing tool 31 to reproduce theshape of the form bar 48 on the periphery of the grinding wheel |8.

It is desirable to provide a safety interlock in case the powertraversing movement of the table is utilized. A normally closed limitswitch 98 (Figs. 1 and 3) is fixedly mounted on a guard plate 9| whichis fixedlymounted to the bracket 15 so that it remains stationary duringthe traversing movement of the bracket 55. An actuating plunger 92 ofthe limit switch 98 rides in end of its stroke before the U-shapedbracket 38 A supporting the follower 39 engages either the arm 48 or thearm 49 to open the circuit and stop the motor 32 which in turn stops thepressure In order to transmit the de-.

'pump' 3|, thereby stopping the table traversing movement before any ofthe parts become damaged. In the normal use of the power traverse of thetable, the table -II is reversed before-the safety switch 90 isactuated. The safety switch 90 is provided only as a safety interlockingmechanism to prevent overrunning of the mechanism duringthe truingoperation.

During the truing operation, the grinding wheel. I8 may be manually orautomatically advanced by actuating the normal wheel feeding mechanismto advance the wheel by the required amount to complete the truingoperation. After the truing operation has been completed, the nut 86 isloosened and the arm 83 swung in a counterclockwise direction (Fig. 2)to disconnect it from the rod 19 so that the table II may be traversedlongitudinally from a truing into a grinding position withouttransmitting any relative igioveigient between the follower 39 and theform ar A The operationof this improved truing apparatus will be readilyapparent from the foregoing disclosure. The forming bar ll is insertedin an operative position supported by the brackets 48 and 49 and isclamped in adjusted position by the screws 52 and 53. The bracket 55 isthen adjusted to align'the axis of the form bar 40 into a predeterminedrelation with the longitudinal movement of the table I I, after whichthe bracket 55 isclamped in adjusted position by means of the clampingscrews 61 and 68. When it is desired to true the grinding wheel it, thetable II is traversed toward'the left to position the reduced endportion 85 of the rod I9 in substantial alignment with the swinging arm83 which is swung in a clockwise direction into the position illustratedin Fig. 3 with the slot 8| engaging the reduced end portion 85 of the.rod 19. The clamping nut 86 is then tightened to lock the rod 18relative to the base Ill. The table may then be traversed longitudinallyto pass the diamond 31 across the periphery of the grinding wheel.During this movement the form bar 40 is held stationary by the rod 19 sothat a transverse movement is imparted to the slide 35 togenerate apredetermined form or shapeon" the periphery of thegrinding wheel l8.After the diamond 31 has been traversed once across the wheel, the wheelIt may then be advanced by the wheel feeding mechanism above mentionedto true oil! an additional amount on the return traverse of the table Il. After a predetermined truing operation has been completed, the arm 83is again disconnected'and the table II traversed toward the right into agrinding position.

It will be readily apparent from the foregoing disclosure that anyforming bar of the'desired shape and contour having cylindrical endportions Ill and il to fit the brackets 48 and I! may be utilized toreproduce its shape upon the periphery of the grinding wheel. It willalso be readily apparent that when a surface of the form bar becomesslightly worn, the bar, as above described, may be readily rotated topresent a fresh forming surface.

It will thus be seen that there has been. provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may bemade of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim: 1. A truing apparatus for a grinding machine having atransversely movable slide, a follower on said slide, a truing tool onsaid slide, means to traverse said slide and truing tool longitudinally,a forming bar having a surface of revolution. a slide to support saidbar, a frame having a slideway for supporting said slide, a swivel ad-Justment for said frame whereby the axis of the forming bar maybeadjusted relative to the lon- 'gitudinal traversing movement of thetruing tool.

2. A truing apparatus for a grinding machine having a transverselymovable slide, a follower on run of the truing tool relative to theforming bar.

3. A truing apparatus forfa grinding machine having atransverselyvmovable slide, a follower mounted on said slide, a truingtool mounted on said slide, a forming bar which is engaged by saidfollower, means including a fluid pressure mechanism having an electricmotor driven pump to traverse said slide relative to the forming bar, an

electrical interlock including a limit switch, and a cam actuated by thetraversing movement of said truing tool to stop said electric motordriven pump so as to stop the traversing movement of the truing tool toprevent an overrun of the truing tool relative to the forming bar.

CARL G. FLYGARE.

